Re: [PATCH v10 01/17] iova: Export alloc_iova_fast() and free_iova_fast()

[Jason Wang <jasowang@redhat.com>]

在 2021/8/5 下午8:34, Yongji Xie 写道:
>> My main point, though, is that if you've already got something else
>> keeping track of the actual addresses, then the way you're using an
>> iova_domain appears to be something you could do with a trivial bitmap
>> allocator. That's why I don't buy the efficiency argument. The main
>> design points of the IOVA allocator are to manage large address spaces
>> while trying to maximise spatial locality to minimise the underlying
>> pagetable usage, and allocating with a flexible limit to support
>> multiple devices with different addressing capabilities in the same
>> address space. If none of those aspects are relevant to the use-case -
>> which AFAICS appears to be true here - then as a general-purpose
>> resource allocator it's rubbish and has an unreasonably massive memory
>> overhead and there are many, many better choices.
>>
> OK, I get your point. Actually we used the genpool allocator in the
> early version. Maybe we can fall back to using it.


I think maybe you can share some perf numbers to see how much 
alloc_iova_fast() can help.

Thanks


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